I second the Eminent Technology suggestion; they seem to be not well known, which is amazing considering their incredible performance. See the recent review of them in vol. 38 of HiFi+ Mag. I have heard the 3.6's several times and would not trade my stacked Eminent LFT-8A's for them. The dual magnet array technology, in my opinion, clearly outperforms the Magnepan technology. I believe the 20.1 version may use the dual magnet technology, which would help explain why it is a world class speaker.
Eminent's certainly give nothing away in terms of performance to Magnepans (imho). At their price point, I don't know of any speaker which could outperform them. That's a pretty bold statement, but when you hear them, you'll possibly agree. Just make sure you do hear them!